Oxide ceramic fiber composite materials as thermal barrier in electricity storage devices

Abstract

The present invention relates to a thermal barrier for battery systems, in particular for rechargeable battery systems, and thus to the use of oxide ceramic composite materials as a thermal barrier in battery and rechargeable battery systems.

Description

[0001] Our reference number: 251205WO EBO / BOE / scs

[0002] Your reference number: 2024 / 249

[0003] September 25, 2025

[0004] Oxide ceramic fiber composites as a thermal barrier in electricity storage systems

[0005] The present invention relates to a thermal barrier for electricity storage devices such as battery systems, in particular also for accumulator systems, and thus to the use of oxide ceramic fiber composite materials as a thermal barrier in such energy storage devices.

[0006] When the present application refers to cells and blocks, this refers to cells and blocks of electricity storage devices such as batteries or accumulators. In particular, the present invention relates to thermal barriers for accumulators, i.e., the use of oxide ceramic fiber composite materials in accumulators.

[0007] Electric mobility is increasing in the context of climate change. In passenger cars and

[0008] Electric propulsion is increasingly used in trucks. Research is still underway on systems that meet the requirements for ships and aircraft. Electricity storage systems used in mobility applications currently consist mostly of lithium-ion batteries or variations thereof. In these systems, aging or mechanical / thermal stress can damage the cells, triggering a so-called "thermal runaway." This produces very hot flames (up to 1300 °C), primarily caused by the combustion of hydrogen with oxygen.

[0009] Electricity storage systems in the mobility sector are typically composed of multiple cells, which are grouped into blocks. Several blocks then form the actual battery or accumulator. Due to this design, three types of thermal runaway can be distinguished:

[0010] • Spread from cell to cell

[0011] • Crossing from block to block

[0012] • Battery's influence on the surrounding mobility system

[0013] In this context, thermal runaway means that, for example, a cell fails and the resulting high temperatures cause the adjacent cell to overheat and also fail. If an entire block fails, there is a risk that this will spread to the adjacent block(s). The risk of thermal runaway is not only due to the risk of cell or block failure caused by the extreme temperatures of up to 1300 °C, but also because cells and / or blocks can be mechanically damaged. During a thermal runaway, overpressure builds up within a cell, leading to its mechanical destruction. This occurs almost explosively, causing components of the cell's casing to be propelled at high speed and potentially damaging surrounding structures.

[0014] Both temperature increases and potential mechanical damage pose a risk to the cells and blocks of energy storage devices. Damage to the surrounding systems of a vehicle cannot be ruled out either. For example, a car could catch fire, endangering people. Furthermore, critical safety systems such as steering or braking systems could be damaged, rendering the vehicle uncontrollable. The same applies to aircraft or other flying machines, which could then crash or be unable to land safely.

[0015] Therefore, manufacturers of vehicles using battery-powered drives must comply with regulations for type approval that are designed to ensure passenger safety. There are stringent requirements for the automotive industry and very stringent requirements for the aviation industry. Manufacturers must ensure that the battery systems do not lead to, or only delay, a systemic failure of the vehicle, and that passengers can avoid the danger of high temperatures and the resulting vehicle fire for as long as possible. This task is addressed differently by each manufacturer, but almost always involves a complex system. An important component of such thermal runaway barriers (TRBs) are heat-insulating barriers designed to reduce the thermal load in the vicinity of a runaway cell, thus delaying or even preventing its propagation.The material solutions currently being used to contain the fire are:

[0016] 1. Aerogels

[0017] 2. Ceramic papers

[0018] 3. Ceramic nonwovens

[0019] 4. Polymers

[0020] 5. Ceramic fiber composites made of non-oxide fibers and a geopolymer matrix

[0021] The state of the art already covers a wide variety of materials and product solutions, each with certain advantages in specific design aspects such as specific weight, thermal insulation, dielectric strength, ease of handling and system integration, shaping possibilities, maximum temperature, mechanical strength in case of fire, and density. The disadvantages of the state of the art must therefore be considered individually.

[0022] Aerogels are complex to manufacture. They are often in the form of granules, which makes them difficult to use in batteries or accumulators. Handling, assembly, and system integration are therefore challenging. While their thermal insulation properties are excellent, aerogels are only stable up to temperatures of approximately 600 °C. Furthermore, they exhibit low mechanical stability.

[0023] Ceramic papers and nonwovens have the disadvantage of not being dimensionally stable. Therefore, processing them in a mobile energy storage device, such as a battery or accumulator, is difficult on an industrial scale. Currently, only manual processing would be possible. Shaping possibilities are limited, as is the insulating effect. Mechanical stability is very low. System integration requires complex auxiliary structures.

[0024] Polymers can be in the form of foams or pods. Most of the foams used are toxic; in particular, they can outgas, which can lead to a further increase in pressure within the energy storage device. Furthermore, most are only stable up to a temperature of approximately 500 °C to 600 °C. Foams also require a large amount of space.

[0025] Carbon fibers are frequently used in a matrix of geopolymers. These are not stable in the presence of oxygen and oxidize, necessitating additional protection and thus the additional costs of a special design. If these additional structures are destroyed during a thermal runaway, the protection against oxygen is no longer effective. If these structures are carbon-based, the fire will also produce smoke. The insulating effect of non-oxide fibers and geopolymers is also inferior to that of other materials, particularly aerogels or ceramic papers or nonwovens.

[0026] Therefore, there remains a need for thermal protection of energy storage systems to safeguard individual cells, blocks, and entire systems from the environment during thermal runaway. This thermal protection must be designed to shield against the temperatures generated by the environment. Simultaneously, the material must be resistant to mechanical stress and withstand the resulting overpressure. Furthermore, the potential for individual components of a cell or block to become ejected during thermal runaway or other structural failure should not cause significant damage to the surrounding material. At the same time, the material must be as lightweight as possible to avoid any significant weight increase in the vehicles.Space requirements for electricity storage devices such as batteries / accumulators (rechargeable batteries) are also usually limited, so a material with high thermal insulation is needed. Applications are not limited to mobility alone.

[0027] Surprisingly, it has been shown that an oxide ceramic fiber composite material is suitable as a thermal barrier in electricity storage devices and essentially avoids the disadvantages of the prior art. In a first embodiment, the problem underlying the present invention is therefore solved by a thermal barrier for electricity storage devices comprising an oxide ceramic fiber composite material, wherein the fiber composite material contains one or more layers of oxide ceramic fibers, in particular long fibers, embedded in an oxide ceramic matrix, and wherein the thermal barrier is configured to prevent or delay the propagation of thermal runaway within the electricity storage device.

[0028] It has been shown that oxide ceramic fiber composite materials can be used as a thermal barrier for electricity storage systems, serving as a barrier against temperature, current, sparks and flames.

[0029] In a preferred embodiment, the thermal barrier consists of the oxide ceramic fiber composite material. One or more layers of the fiber composite material can be used.

[0030] The gases produced during thermal runaway in electricity storage devices, if they cannot be vented, lead to a pressure build-up and thus an increased risk of explosions. A material with a porous structure allows the controlled diffusion of gases produced during thermal instability, thereby controlling the pressure build-up and preventing explosions. In a preferred embodiment, the thermal barrier has a porous structure.

[0031] Preferably, the thermal barriers according to the invention have a density of 0.5 g / cm³. 3 up to 4 g / cm² 3 , especially in the range of 1 g / cm³ 3 up to 3 g / cm² 3 , especially preferred at 1 g / cm² 3 up to 2 g / cm² 3 This allows for good insulation properties while maintaining sufficient mechanical stability and low weight.

[0032] The thermal barrier according to the invention thus comprises an oxide ceramic fiber composite material. This fiber composite material comprises oxide ceramic long fibers which are embedded in an oxide ceramic matrix.

[0033] Ceramic matrix composites (CMCs) consist of two main components: a ceramic fiber component and a ceramic matrix that surrounds and binds the fibers together. The appropriate combination of these two main components enables damage-tolerant failure of the otherwise typically brittle ceramics. Damage-tolerant failure can be achieved in various ways and depends, among other things, on the matrix system used, the fibers used, and the fiber-matrix bonding. According to the invention, the fibers can preferably be in the form of woven fabrics, nonwovens, braids, or similar fiber preforms made from long or continuous fibers, such as fleeces, felts, papers, or similar materials, in each case as ID, 2D, or even 3D fiber structures.According to the invention, the fibers are in particular ceramic, silicate, mineral, and / or glass fibers. Furthermore, basalt fibers or pyrolyzed natural fibers can also be used in a preferred embodiment. According to a preferred embodiment of the present invention, the oxide ceramic long fibers comprise materials selected from the group consisting of Al₂O₃, Si₂O₃, ZrO₂O₃, TiO₂O₃, MgO, ZnO, BaO, mullite, and mixtures thereof. Particularly preferably, the oxide ceramic long fibers comprise materials selected from the group consisting of Al₂O₃, SiO₂O₃, mullite, and mixtures thereof, in particular Al₂O₃ and / or SiO₂.

[0034] The ceramic matrix is, for example, based on oxide ceramic particles. According to a preferred embodiment of the present invention, the oxide ceramic particles comprise materials selected from the group consisting of Al₂O₃, Si₂O₃, Zr₂O₃, Ti₂O₃, MgO, ZnO, and mixtures thereof. Particularly preferably, the oxide ceramic particles comprise materials selected from the group consisting of Al₂O₃, Si₂O₃, Zr₂O₃, and mixtures thereof, in particular Al₂O₃ and / or Si₂O₃.

[0035] The components of the oxide ceramic fiber composites according to the invention, namely the oxide ceramic long fibers and the oxide ceramic matrix, can consist of the same or different materials. In both variants, the fibers and the matrix are preferably crystalline, with the matrix also potentially containing amorphous components. The long fibers and the matrix are distinguishable from one another using microscopic methods known to those skilled in the art, even if both are completely crystalline and comprise the same materials. In a preferred embodiment, the oxide ceramic long fibers are completely crystalline and the oxide ceramic matrix is ​​partially crystalline. The matrix can therefore contain amorphous components.

[0036] Surprisingly, it has been shown that these oxide ceramic fiber composites are particularly suitable for use as a thermal barrier in electricity storage systems.

[0037] In a preferred embodiment, the oxide ceramic fiber composites consisting of one or more layers of woven fabric made of oxide ceramic long fibers embedded in an oxide ceramic matrix are used as a thermal barrier according to the present invention.

[0038] The material used according to the invention effectively reduces the thermal stress in the vicinity of a failing cell and thus delays or prevents the propagation of thermal instability to neighboring cells or blocks, or to the overall system surrounding the energy storage device. The material according to the invention therefore also provides thermal and electrical insulation. Furthermore, the material offers protection against erosion from sparks and against mechanical damage, which can occur, for example, due to the explosive lifting of the cell lid on downstream components and structures.

[0039] According to the invention, preventing or delaying the propagation of thermal runaway means that the surrounding material is not damaged in the following test due to the thermal and mechanical expansion caused by the runaway to such an extent that it can no longer perform its protective function: An NCM lithium-ion cylindrical cell with a capacity of 23 Ah is positioned so that its degassing opening is at a distance of 20 mm from the thermal protection barrier according to the invention, which has a thickness of 1.5 mm.

[0040] The cell is fully charged (100% state of charge) and fixed in a test fixture at an ambient temperature of 25°C. The test is performed by axially penetrating the cell with a metallic nail.

[0041] Current, voltage, and temperature were continuously measured over a period of 1000 seconds using the following devices. The data were recorded directly at the corresponding surface of the thermal barrier:

[0042] - Battery cell cycler (Arbin LBT21084 8xlOA, SN 202551)

[0043] - Data acquisition system (Gantner Q. station XT with Q.bloxx XL A127, A104 and A107, serial number 755186).

[0044] - Multimeter (Fluke 115).

[0045] As soon as the nail penetrates the cell axially, a short circuit occurs, causing the voltage to drop immediately to 0 V. At this moment, the cell wall temperature rises exponentially to 900 °C. Potential gas and flames can also reach even higher temperatures (up to 1500 °C) for short periods; however, these are not considered in this measurement.

[0046] Provided the thermal barrier on the side facing away from the cell, i.e., the outer side of the thermal barrier, shows no significant material damage such as perforations and / or reaches a maximum temperature below 250 °C, the thermal barrier prevents or delays the propagation of thermal runaway. The main criteria, besides the temperature on the back side, are that no fire, smoke, or gas leakage occurs on the side facing away from the cell.

[0047] In particular, the thermal barrier according to the invention ensures mechanical integrity, as it withstands the sudden pressure increase and the bombardment by fragments (e.g., parts of the cell casing, electrode material) released when the cell ruptures. The thermal barrier must maintain its structural integrity to prevent the penetration of these fragments and to protect the surrounding structure. The barrier must withstand the hot, high-pressure jet of gas and particles escaping without perforation or significant material loss that would impair its protective function.

[0048] In a preferred embodiment, the thermal barrier, for which the oxide ceramic fiber composites according to the invention are used, is implemented between battery cell / battery block / battery / system units. In this preferred embodiment, a unit is, for example, a unit of battery cell to battery cell, battery block to battery, etc. The slash " / " is intended to represent a selection of the respective subunit (battery cell / battery block / battery / system) that, together with another subunit, forms the so-called unit. The subunits can be identical or different, so that all combinations of the individual subunits forming the units are possible in this preferred embodiment.In a particularly preferred embodiment, the thermal barrier, for which the oxide ceramic fiber composites according to the invention are used, is implemented between battery units or systems, and even more preferably between battery units or systems. In a further preferred embodiment, the thermal barrier, for which the oxide ceramic fiber composites according to the invention are used, is implemented between battery blocks.

[0049] In this embodiment, a battery is a complete, ready-to-use energy unit comprising at least one battery block consisting of at least two battery cells and being fully functional. Accordingly, the battery may also include additional necessary components such as the battery management system (BMS), cooling, wiring, and housing.

[0050] In this embodiment, a system is the complete unit powered by the battery, i.e., the end product in which the battery is installed. If the thermal barrier according to the invention is arranged between the battery and the system, it protects the internal structure and the outer casing of the product from damage caused by thermal runaway.

[0051] In this embodiment, the term "battery block" refers to a unit consisting of several electrically interconnected battery cells, which can be understood as an intermediate stage between a single battery cell and a complete battery. A battery block may have a common housing as well as electrical contacts for connection with other battery blocks and / or a battery.

[0052] For the purposes of the present invention, the term "battery" also includes accumulators, i.e., rechargeable electricity storage devices.

[0053] Unlike other materials such as aerogels, ceramic nonwovens, ceramic papers, or polymer foams, oxide ceramic fiber composites retain their mechanical stability even at high temperatures (>1000 °C) and are significantly more resistant to mechanical degradation caused by erosion resulting from the ejection of metallic particles or the detachment of the battery cell lid during cell combustion. Furthermore, they maintain their complete mechanical integrity throughout their entire service life, even in systems subject to strong vibration. Oxide ceramic fiber composites are also electrically insulating, chemically inert, and exhibit low thermal conductivity (<3 W / mK).

[0054] The material can be configured in various forms, e.g. as plates, sandwich structures or even in complex geometries such as honeycombs, to suit different battery system designs.

[0055] These technical effects improve the overall safety and reliability of electricity storage systems, especially mobile electricity storage systems in various applications, including electric vehicles, aircraft and industrial robots.

[0056] In a preferred embodiment, the oxide ceramic fiber composite material used according to the invention has a thickness of 0.2 mm to 10 cm, in particular of 0.5 mm to 5 cm, preferably of 1 mm to 10 mm, and / or the thermal barrier as which the oxide ceramic fiber composite material is used according to the invention has a density of 0.5 g / cm³. 3 up to 4 g / cm² 3 , especially of 1 g / cm³ 3 up to 3 g / cm² 3Thinner materials, or those with a density outside the required range, do not exhibit the desired properties regarding thermal insulation and mechanical stability. Thicker fiber composite materials require too much space and are too heavy, making them undesirable for typical vehicle applications.

[0057] In this thickness range, the material provides sufficient thermal stability up to 1400 °C, which can be achieved when passing through cells, particularly blocks. In a preferred embodiment, the oxide ceramic long fibers used according to the invention are present in the thermal barrier as woven fabric, nonwoven fabric, or short fibers, including combinations thereof.

[0058] In a preferred embodiment, in addition to the oxide ceramic long fibers used according to the invention, at least one further insulating material is present in the thermal barrier. It is further preferred that the insulating material is selected from aerogels, ceramic nonwovens, ceramic papers, foams, and / or polymers. Such insulating materials are well known and can be present in addition to the thermal barrier according to the invention. However, it should be emphasized again that these known insulating materials have disadvantages, as already explained above.

[0059] According to the invention, a thermal barrier can be constructed, for example, in the form of a sandwich structure, wherein the oxide ceramic fiber composites each constitute an outer layer and a ceramic nonwoven or ceramic paper is inserted between the outer layers. The fiber composite material according to the invention offers excellent mechanical protection of the component to be insulated while simultaneously exhibiting good thermal insulation properties. Due to the porosity of the oxide ceramic fiber composites, bonding by adhesive bonding or lamination is possible. It is also possible that, through suitable manufacturing processes, the ceramic nonwoven or ceramic paper can be incorporated directly between the fiber composites.If the oxide ceramic fiber composites are produced, for example, using a device as described in EP 4 194 168 Al, the ceramic nonwoven or paper can be introduced into the mold between the fiber layers. The slurry does not necessarily penetrate the ceramic nonwoven or ceramic paper completely. However, it is then firmly bonded to the fiber composite. According to the invention, it is also possible for the oxide ceramic fiber composite to be provided in the form of a container, which is then filled with aerogel granules. It is also possible to provide aerogels in sheets, which are then sandwiched between the oxide ceramic fiber composites.

[0060] In a preferred embodiment, the oxide ceramic long fiber layers used according to the invention are constructed in a sandwich design; in particular, the sandwich design provides a cavity which is closed or openly spanned by two oxide ceramic long fiber layers.

[0061] In an advantageous embodiment, the oxide ceramic long-fiber layers in this sandwich construction can differ from one another in terms of their composition and / or properties, but they can also be identical. For example, the layer facing the cell can consist of a material with very good mechanical properties. In contrast, an adjacent second layer can have lower mechanical stability but provide improved thermal insulation. In a further preferred embodiment, another mechanically intact layer can be provided, which offers additional strength and protection against external influences. In a particularly preferred embodiment of the thermal barrier, at least one layer is formed from an oxide ceramic fiber composite material according to the invention, which in turn is composed of several layers of fabric.Further layers can be used to achieve an optimized combination of mechanical strength, thermal insulation, and erosion resistance through the use of different materials. Figure 6 schematically shows various embodiments according to the invention for the use of oxide ceramic fiber composites as a thermal barrier. Embodiment 6A shows a variant in which the thermal barrier according to the invention consists exclusively of an oxide ceramic fiber composite material (i).

[0062] Embodiment 6B shows an embodiment with a first oxide ceramic fiber composite material (i) and a different second oxide ceramic fiber composite material (ii). The first (i) and second fiber composite material (ii) can differ in the type of fiber and / or the type of matrix.

[0063] Embodiment 6C shows a sandwich structure consisting of a first oxide ceramic fiber composite material (i) and a second oxide ceramic fiber composite material (ii) that is different from the first. The second outer surface also features either the first oxide ceramic fiber composite material (i) or a third oxide ceramic fiber composite material (iii) that is different from the first and second.

[0064] In embodiments 6B and 6C, the first (i) and / or second (ii) and / or third (iii) oxide ceramic fiber composite material can have the same thickness or different thicknesses.

[0065] Embodiment 6D is a variant of embodiment 6B, wherein one of the fiber composite materials is coated. The coated fiber composite material (iv) can also be sandwiched on both sides with an oxide ceramic fiber composite material (analogous to embodiment 6C), whereby the two outer fiber composite materials can be the same or different. It is also possible, in accordance with embodiment 6A, to use only one coated fiber composite material. Embodiment 6E shows at least two outer oxide ceramic fiber composite materials (i, ii, iii), which can be the same or different. Between these is a cavity (v). This cavity can be filled with a material different from the fiber composite material, such as air, aerogels, polymer foam, polymer granules, etc.

[0066] In a further preferred embodiment, a coating is applied to the surface of the oxide ceramic fiber composite material used according to the invention, wherein the coating is in particular selected from the group consisting of polymer, glass, inorganic, metallic and ceramic coatings.

[0067] Such a coating can further optimize the properties of the thermal barrier. For example, the coating of the fiber-reinforced composites used according to the invention can also exhibit a thermal barrier effect. Alternatively, it can be a coating that releases CO2 or another material when exposed to heat, which prevents a fire or dampens its spread. It is also possible to select the coating in such a way that the thermal barrier is no longer porous and, for example, the supply of oxygen from the outside is restricted.

[0068] Embodiment 6F shows the use of such an oxide ceramic fiber composite material (vi) in which the porous structure of the oxide ceramic fiber composite material is partially or completely provided with a further component (coating). This results in a sealing effect. In the event of a fire, a reservoir of flame-retardant material is available, since the coating comprises and, in particular, consists of a flame-retardant material. A coated ceramic fiber composite material (6) used according to the invention and in this manner can also be combined with other materials analogously to embodiments 6B or 6C.

[0069] The thermal barrier and, in particular, the oxide ceramic fiber composite materials used as such, have a porosity of 0 vol.% to 90 vol.%, preferably 20 vol.% to 60 vol.%.

[0070] It can be stated that the fiber composite materials according to the invention can be used alone or in combination with other materials, as previously explained.

[0071] In a further embodiment, the present invention relates to an electricity storage device comprising a plurality of cells which are grouped into at least one block, having a thermal barrier which is provided according to the present invention.

[0072] The designs can be in various geometries derived from the plane (deep-drawn) and adapted to the requirements of the three fire scenarios:

[0073] 1. Cell to cell

[0074] 2. Battery block to block

[0075] 3. The battery can be adapted to the system. The components can have a wave or honeycomb structure and be nested within each other to be installed around individual battery cells, thus integrating them in a space-saving manner. The components can be designed as sleeves. The components can be installed vertically or horizontally to the cells in a plate-like fashion. Several versions can be combined within a battery system. Fig. 1 schematically shows the use of oxide ceramic fiber composite materials according to the invention as a thermal barrier to prevent heat transfer from cell to cell. The thermal barrier is shown with a dashed line. The cells are shown in the form of a cylinder. Heat transfer is indicated by a black arrow.

[0076] Similarly, Fig. 2 schematically shows the overlapping of the penetration from one block to the next and to a third. Here, too, the use of oxide ceramic fiber composites as a thermal barrier according to the invention is shown in dashed lines, the overlapping by arrows and blocks by the grouping of round cells (top view of the cells).

[0077] Fig. 3 shows the propagation (black arrows) of heat passing through an electricity storage device to the surrounding environment. Here, too, the use of oxide ceramic fiber composites as a thermal barrier according to the invention is shown in a dashed line.

[0078] Fig. 4 shows possible embodiments of the arrangement of the oxide ceramic fiber composites (1, IB, 1C) used as a thermal barrier according to the invention between the cells (2, 2B, 2C) of an electricity storage device. This can be realized as flat plates (1) (Fig. 4A), corrugated plates (IB) (Fig. 4B), or nested (Fig. 4C). The nesting can be achieved with a flat plate or a corrugated plate that can be connected by means of cuts (3) in the plates (1B and 1C). The interfaces are cut, for example, to half the width (Fig. 4C2), so that the nesting can be achieved by inserting and then twisting the plates. The arrangement can also be made between the blocks accordingly. When using oxide ceramic fiber composites as a thermal barrier for the electricity storage device as a whole, the thermal barrier can, for example, be arranged only on one of the outer sides, as in Fig.Figure 3 shows. However, according to the invention, it is also possible for the thermal barrier to be arranged on other outer surfaces and to be part of the housing element, as schematically shown in Figure 5. In this case, the battery cell (4), as a block or the complete unit, is integrated into a housing element that includes the oxide ceramic fiber composite material (5, 5A, 5B). The geometry of the housing or of the oxide ceramic fiber composite material can be flat or adapted to the contour of the battery cell (4). The housing or several sides of the housing can be manufactured integrally or modularly.

[0079] The oxide ceramic fiber composite materials can be formed, for example, into sheets, grids, honeycomb structures, or sleeves. The cells or blocks can then be inserted into these.

[0080] The method disclosed in EP 4 194 168 Al for manufacturing components from ceramic fiber composites with variable geometry is a vacuum pressure infusion and drying process with which components made of oxide ceramic fiber composites can be manufactured automatically in a continuous process without manual intermediate steps. Due to their special structure, described in more detail in EP 4 194 168 Al, the resulting components made of oxide ceramic fiber composites exhibit quasi-ductile and thus damage-tolerant deformation behavior. It was surprisingly found that this method is particularly suitable for manufacturing energy storage devices according to the invention, especially for producing the thermal barrier used in these devices according to the invention.In a further embodiment, the present invention relates to a method for producing a thermal barrier according to the invention, wherein at least one layer of an oxide ceramic fiber composite material is provided and the material is treated such that a thermal barrier according to the invention results, in particular in the form of plates, grids, honeycombs or sleeves. Other methods for production are known to those skilled in the art and can also be used to obtain the thermal barrier according to the invention.

[0081] Regardless of the specific design, the thermal barrier can also have other features, such as penetrations that result from the functioning of the entire system and whose geometric form may deviate arbitrarily from a pure plate geometry.

[0082] The electricity storage devices according to the invention can be used, for example, in

[0083] • Battery-electric powered aircraft (drones, eVTOLs, airplanes)

[0084] • Battery-electric vehicles (cars / trucks / buses)

[0085] • Battery-powered industrial robots

[0086] • Battery storage systems

[0087] • Battery-electrically powered ships

[0088] In a preferred embodiment, the electricity storage devices are those of battery-electric aircraft, motor vehicles, trucks, watercraft, spacecraft, or industrial robots, which are used particularly for passenger transport and are especially capable of autonomous movement. Use in stationary electricity storage systems is also possible. The thermal barrier according to the invention allows the mechanical integrity of the respective product to be maintained in the event of thermal runaway when used in the aforementioned vehicles, watercraft, spacecraft, or industrial robots. In this way, the outer casing, in particular, is effectively protected from damage despite battery failure.

Claims

Patent claims 1. Thermal barrier for electricity storage comprising an oxide ceramic fiber composite material, wherein the fiber composite material contains one or more layers of oxide ceramic fibers, in particular long fibers, embedded in an oxide ceramic matrix, and wherein the thermal barrier is configured to prevent or delay the propagation of thermal runaway within the electricity storage device.

2. Thermal barrier according to claim 1, characterized in that it consists of the oxide ceramic fiber composite material.

3. Thermal barrier according to the preceding claims, characterized in that the thermal barrier has a porous structure.

4. Use of oxide ceramic fiber composites consisting of one or more layers of oxide ceramic long fibers embedded in an oxide ceramic matrix as a thermal barrier according to at least one of claims 1 to 3 in electricity storage devices.

5. Use according to claim 4, characterized in that the thermal protection barrier is realized in relation to units battery cell / battery block / battery / system to battery cell / battery block to battery block and / battery / to system.

6. Use according to at least one of claims 4 or 5, characterized in that the oxide ceramic fiber composite material has a thickness of 0.2 mm to 10 cm, in particular of 0.5 mm to 5 cm, preferably of 1 mm to 10 mm, and / or the thermal barriers have a density of 0.5 g / cm³ 3 up to 4 g / cm² 3 , especially of 1 g / cm³ 3 up to 3 g / cm² 3 exhibits.

7. Use according to at least one of claims 4 to 6, characterized in that the oxide ceramic long fibers in the thermal barrier are present as a laid or woven fabric or nonwoven, including a combination thereof.

8. Use according to at least one of claims 4 to 7, characterized in that, in addition to the oxide ceramic long fibers in the thermal barrier, at least one further insulating material is present.

9. Use according to claim 8, characterized in that the insulating material is selected from aerogels, ceramic nonwovens, ceramic papers, foams and / or polymers.

10. Use according to at least one of claims 4 to 9, characterized in that the oxide ceramic long fiber layers are constructed in a sandwich structure, in particular the sandwich structure provides a cavity which is closed or openly spanned by two oxide ceramic long fiber layers.

11. Use according to at least one of claims 4 to 10, characterized in that a coating is applied to the surface of the oxide ceramic fiber composite material, wherein the coating is in particular selected from the group consisting of polymer, glass, inorganic, metallic and ceramic coatings 12. Use according to at least one of claims 4 to 11, characterized in that the electricity storage devices are those of battery-electrically powered aircraft, motor vehicles, trucks, watercraft, etc. These are vehicles, spacecraft or industrial robots that are used especially for passenger transport and move autonomously.

13. Electricity storage device comprising a plurality of cells which are grouped into at least one block, having a thermal barrier according to at least one of claims 1 to 3.

14. Method for manufacturing an electricity storage device according to claim 13, characterized in that at least one layer of an oxide ceramic fiber composite material is provided and the material is treated, preferably by deep drawing, in such a way that a thermal barrier according to at least one of claims 1 to 3, in particular in the form of plates, grids, honeycombs or sleeves, results.

15. Method according to claim 14, characterized in that the thermal barrier is provided fully automatically.

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